The present invention relates to machine tools and, more particularly, to hand-retractable plungers for use with machine tools.
Hand-retractable plungers are a common component of machine tools and are used to position parts of the tool, such as cutting implements, workpiece supports and the like, relative to the rest of the tool. Typically, such plungers include a handle portion of a pre-selected shape permanently attached to a spring-loaded plunger slidably received within a threaded barrel. The barrel is threaded into a component of a machine tool such that the end of the plunger opposite the handle portion protrudes from the component. The handle portion can be pulled to retract the plunger end into the barrel to provide clearance so that the component can be moved relative to the machine tool. When the component has been positioned as desired, the handle is released, thereby releasing the plunger, which then protrudes from the barrel and component into a locating hole on the machine tool.
The handle portion of a hand-retractable plunger may be a pull ring, bar, knurled knob or any other like knob or handle that allows a user to grip the plunger firmly. However, a disadvantage with current hand-retractable plungers is that a user may desire to use a plunger with a specific handle portion, or may wish to change the type of handle portion used on a particular plunger. Such a decision is typically based on user comfort, safety, or the particular application of the plunger. However, at present, changing the type of handle portion requires replacing the entire hand-retractable plunger.
Accordingly, there is a need for a hand-retractable plunger that can be adapted to accommodate a plurality of handle types and sizes.